Either use questions (how old are you?, when is your birthday? etc) or flashcards. Flashcards make the game go much quicker, increasing the level of energy.
I play with all students standing up. I either ask a question or flash a card. The first student to raise his hand and say the English word for the picture card or answer the question can choose to either have the pupils standing in his/her horizontal row or vertical column to sit down (technically "saving" their friends). Keep going until one student or a row/column is left standing. I sometimes feel bad having only one student left standing so usually ask the last few people standing a question they can answer together.